1. Field of the Invention
The present invention relates to an information processing apparatus, a control method of the same, and a computer program.
2. Description of the Related Art
To back up data electronically stored in various devices, the conventional approach is to back up the data in external storage devices different from the devices storing the original data. Especially when data is to be periodically backed up, the data is often backed up in an offline medium such as a magnetic tape, CD-R, or DVD-R by using a writing apparatus for the medium.
For example, when all or some of files stored in a hard disk drive as a storage device of a general-purpose computer are to be backed up, the backup data can be recorded on a magnetic tape by using a tape drive connected to the computer. The backup data may also be recorded on a DVD-R disk by using a DVD-R drive.
The backup methods are roughly classified into full backup and incremental backup. Full backup is a method which backs up all files to be backup when backup is to be performed. In one full backup method, a file to be backup is archived by using an archive command such as a tar command of the UNIX (registered trademark) operating system, thereby forming backup data. In another full backup method, backup data which is the same as a file to be backup is formed. Incremental backup is a method which backs up only files which have been added and/or updated since the last backup. To restore the data, therefore, the data must be combined with the last backup data.
It is also possible to restore data by combining full backup data and incremental backup data. However, this method has the problem that files which have been deleted from the timing of full backup to the timing of incremental backup are also restored. To solve this problem, a method which records identification data of files deleted from the full backup timing to the incremental backup timing and does not restore the deleted data during restoration is proposed (Japanese Patent Laid-Open No. 10-214214).
In the conventional backup methods, however, even when data stored in various devices for backup is to be completely deleted, it is difficult to delete this data alone from the backup data. For example, when backup data is to be formed by full backup, it is difficult to delete only a specific file from the backup data. This poses the problem that even when the original data is deleted, the same data as the original data remains in the backup data.
Even when backup data has the same contents as the original, if this backup data is recorded on an unrewritable offline medium such as a DVD-R disk, no specific file alone can be deleted. Accordingly, the only way to delete the backup data is to physically destroy the whole medium. Note that if a backup medium is a rewritable medium such as a DVD-RW, a specific file alone can be deleted.
When full backup is periodically performed, however, a large number of offline media storing backup data may exist. If a specific file alone is to be deleted in a case like this, it is necessary to delete this file alone from all the large number of offline media. This makes it necessary to repetitively perform the process of loading each offline medium into a recording apparatus, and deleting the specific file. The process is cumbersome, and is also unrealistic from the viewpoint of cost. Incremental backup also has the same problem.
Recently, Personal Information Protection Act is established, so it is required to make unnecessary data completely unusable more often than before. Accordingly, the inability to delete backup data as described above may have serious influence from the viewpoint of protection and management of personal information.